Phonograph



Oct. 8, 1935. l T. c. BROWN 2,015,887

PHONOGRAPH Filed Jan. 23, 1932 Patented Oct. 8, 1935 UNITED STAT-Es PATENT OFFICE PHONOGRAPH Application January 23, 1932, Serial No. 588,274

11 Claims.

This invention relates to phonographs and more particularly to back spacing mechanisms for commercial phonographs.

It has been found desirable in commercial phonographs to provide means for the user of the phonograph to back space the sound box occasionally in order that it may repeat portions of matter recorded on the record cylinder. It is also desirable that the means for controlling such back spacing be located at a point remotefrorn the phonograph itself, and in the case of a transcribing machine at a point adjacent the keyboard of the typewriter of the transcribing operator. It has been found that these results *v can be most easily and best accomplished by employing electro-magnetic means to supply the energy for causing the back spacing operation and providing a simple electrical switch for the operator so that the function of back spacing may be performed quickly and easily and at any distance from theoperating machine. However, because of the small space available on the commercial type of phonograph, it is desirable to limit the size of the electromagnet as far as possible. Furthermore, when operating a back spacing mechanism it is usually desirable to supply a rather large amount of energy to such mechanism in order that it shall operate quickly and reliably. These conditions impose considerable diiculty on the designer since if a large amount of current is allowed to circulate in an electromagnet of small size, there is likely to be considerable heating with consequent damage to the coil. Mechanisms of this general type are shown in Holland Patent No. 1,275,257 granted August 13, 1913, and in Gramann Patent No. 1,979,829, granted November 6, 1934. In order to obviate overheating oi' the coil, apparatus: has been designed wherein the circuit of the electro- 40 magnetic back spacing device is automatically opened after it has been closed by the operator, so that if more than one back spacing operation is required, it is necessary that the operator release and then again press an operating key for each subsequent operation. Such an apparatus is shown in Durand Patent No. 1,733,951 granted October 29, 1929.

It is an object of this invention to provide new and improved means for opening the circuit of an electrical back spacing device automatically after it has been closed by the operator.

It is a further object of this invention to provide an electrically operated back spacing device 55 in` which. it is impossible for the operator to continuously energize the electro-magnetic operating means.

Another object of this invention is to provide an electrically opera-ted back spacing device which will, when desired, cause a plurality of suc- 5 c-essive back spacing movements upon a single depression of an operating or control member.

Further objects and features of this invention will be set forth in the following specification and appended claims. 10

For a clearer understanding of my invention, reference may be had to the drawing accompanying and forming part of this specication where- Fig. 1 is a plan vieW of a portion of a com- 15 mercial phonograph with one embodiment of my invention applied thereto, parts being broken away.

Fig. 2 is a side view, partly in section, of the traveling carriage and sound box of the phono- 20 graph shown in Fig. 1. l

Fig. 3 is a detail of the back spacing mechanism.

Fig. 4 is a detail of the electro-magnetic actuating means and the controlling means therefor. 25 Fig. 5 is a detailed View showing a modification of the electro-magnetic operating and control means.

Referring to the drawing, the phonograph consists of a base I with an upright standard 2 sup'- 30 porting ends of the guide rods 3 and 4. A carriage 5 supporting a sound box 6 is mounted for sliding motion on guide rods 3 and 4. The sound box 6 has a stylus arm I@ provided with a stylus IilA adapted to be moved by the carriage across 35- a record tablet 'I mounted on the rotatable mandrel 8. A feed screw 9 geared in any suitable way to the mandrel 3, is provided to cause the carriage 5 to move transversely across the surface of the record tablet l. The arm 5 at its right hand end 40 has two ilanges I5 suitably drilled to hold a bushing It which is arranged to receive the rear guide rod 3. The bushing I6 extends through both of the flanges I5 and across the space intervening them. A U-shaped member consisting of two side arms I'l and a rear portion I8 is pivotally mounted on the bushing I6 in the space intervening the flanges I5. The rear portion I8 of the U-shaped member is bent as shown in section in Fig. 2, and supports a shoulder bolt I9 on which is rotatably 5U mounted a gear wheel 20 with its sleeve I2, and a worm gear I I, the hub of the latter being fastened to the sleeve I2 by means of a set screw I3. Rotatably mounted on the bushing I6 between the arms I7 of the U-shaped member is 55 a cam 4l carrying a pin 43 which passes thru a circumferential slot 42 in the bushing I6 into engagement with a slot 26 in the guide rod 3. A pawl 25 is pivotally mounted on the cam 4I by means of a shoulder screw 55, and is adapted to engage a ratchet wheel 23 which is also mounted for rotation on the bushing I6. A worm 24 is concentrically fastened to the ratchet Wheel 23 and engages the gear wheel 20.

A at leaf spring 2I is adjustably mounted on the right hand flange I5 and presses on a pin. 22 mounted in the side arm I1 of the U-shaped member. This spring constantly presses the U- shaped member in a counter-clockwise direction as seen in Fig. 2, and consequently normally presses the worm gear I I against the feed screw 9.

The back rod 3 is rotatably mounted in the standard 2, and has the slot or keyway 26 cut therein for its entire length. An arm 21 is clamped on the rod 3 for the purpose of rocking this rod a slight amount. A link 29 is fastened to the outer end of the arm 21 by means of a pin 28, and the lower end of the link 29 is fastened to the U-shaped armature 3I adapted to be actuated by electro-magnetic operating means. This means has a coil 34 provided with a core 33 of magnetic material. The armature 3I is also made of magnetic material and is pivoted at 32. This armature carries a bracket 35 on which is mounted a small glass tube 36 partially filled with mercury. Two electrodes or contacts 31 are fitted into the ends of this tube so that when the tube is in the horizontal position shown, the mercury establishes electrical connection between the electrodes. An electrical circuit is then completed through a conductor 40, a push button 38, a battery 39, a conductor 40', the coil 34, and a conductor 40".

It will be seen that when the apparatus is operating normally, the worm gear I I is held against rotation by the gear wheel 20 meshing with the worm 24. Under these circumstances, the worm gear I I acts as a feed nut and when the mandrel 8 and feed screw 9 are rotated, causes the carriage 5 to be advanced across the record.

The operation of the back 'spacing mechanism supported by the carriage, is as follows: The actuating member for the back spacing mechanism Aconsists of the electromagnet 34. 'Ihe magnet when energized actuates the armature 3| with the link 23 to cause the back rod 3 to rock through a small arc in a clockwise direction, as hereinafter described. Since the end of pin 43 is located within the slot 26, the cam 4I to which the pin 33 is fastened is thereupon turned in a clockwise direction as seen in Fig. 2. Since the cam 4I carries the pawl 25, a slight rotary movement is also imparted to the ratchet wheel 23 and consequently to the worm 24. This movement of the worm 24 causes the gear wheel 20 to turn along with its sleeve I2 and the worm gear II. The gear I I then rolls backwardly along the feed screw 3 which coacts therewith as a rack. It will therefore be seen that a back spacing motion of predetermined extent is thus given to the carriage. The cam 4I in the movement thereof described, also actuat/es the pivoted arm or lever 60 to eifect the centering of the stylus ISA with respect to the sound box 6 substantially at the completion of the back spacing movement of the carriage, as described in detail in Gramann Patent No. 1,979,829 granted November 6, 1934. As the armature 3i returns to original position under the influence of gravity, rotary movement is thereby imparted to the back rod 3 in the direction opposite to that described above and carries with it the cam 4I and the pawl 25. The worm gear I I remains locked in the position to which it was carried during the back spacing operation and is ready to again act as a feed nut for advancing the 5 carriage, provided no further back spacing is desired. The pawl 25 has then been positioned to engage another tooth of the ratchet wheel 23 in preparation for a further back spacing operation. Fora more complete description of the back spac- 10 ing mechanism, reference should be made to the pending Gramann application referred to above. The rocking motion imparted to the rear rod 3 is effected by pressing key 38, thus sending a current through the coil 35 and energizing the core l5 33, which thereupon draws the armature 3l upwardly from its position in Fig. 4. In the absence of other circuit breaking means, this armature 3I would remain opposite the core 33 as long as the,key 38 remained depressed. Thus if the 20 operator wanted more than one back spacing operation it would be necessary to release the key 38 so as to de-energize the electromagnet and cause the armature to resume its original position under the influence of gravity, and to then press and 25 release the key successively until the desired number of back spacing movements are effected. However, by provision of the switch 35, such operation of the key is rendered unnecessary. It will be seen that as the armature 3I with its bracket 30 35 is moved upwardly toward the core 33, the mercury in the glass tube 3G will run toward the right hand end of the tube and consequently after a short time interval due to the inertia of the mercury, the electrical circuit will be opened. 35 Immediately upon this opening of the circuit, the coil 34 will be deenergized and consequently the armature 3l with its associated mechanism will fall back to its original position, shown in Fig. 4. However, when it returns to its original position 40 the tube 35 will again assume the horizontal position shown and the mercury therein will flow to the left and establish electrical connection between the two electrodes 31 so that if the key 3B is maintained depressed a circuit will again be made 45 and the back spacing operation repeated. Therefore as long as the key 38 is maintained depressed, successive back spacing operations are obtained, and the sound box is automatically returned toward the beginning of the record. 50 The apparatus shown in Fig. 4 is apreferred embodiment of this invention. In order to be practicable the back spacing movements should not recur too rapidly. It should be possible for the operator to depress the key 38 and secure only a 55 single back spacing operation without having to remove the pressure on the key too rapidly. The control device comprising the mercury switch ensures this result because the inertia of the mer- Vcury is sufficiently sluggish to retard the entire 60 operation.

Fig. 5 shows a modification, the parts of which may readily be properly designed to give a sufliciently slow motion. In this case the armature 3l carries a block of insulating material 46 on 65 which is mounted, by means of screws ll1, a contact arm 44. On the base 50 of the electromagnet is mounted another piece of insulating material 48 to which is fastened a spring contact arm 45 of the form shown. In this case the elec- 70 trical circuit is from the battery 39, through the conductor 5I, to the spring Contact arm 45, then through the contact arm 44, conducto-r 53, the coil 34 and terminals 54, conductor 52, switch 38, and conductor 52 back to the battery. It will be seen 75 that when the button 38 is depressed current will iiow in the core 3d and consequently the magnet will be energized. The armature 3| will then be pulled upwardly and this pull will continue until the arm Ml on the armature 3| clears the end of the spring contact 45, whereupon the circuit will again be broken and the parts will return to the positions shown and the operation may be repeated.

Having thus described my invention, I claim:

l. In a phonograph, a carriage, a sound box mounted on the carriage, means to back space said carriage predetermined amounts, and means comprising an electric circuit, an electromagnet in said circuit for actuating said means, and a control device, which magnet upon a single actuation of such device may successively actuate said back spacing means, said circuit including a switch movable by said back spacing means to open and close said circuit upon each operation of such means.

2. In a phonograph, a carriage, a sound box mounted on the carriage and having a stylus adapted to track a record tablet, means for back spacing the carriage, an electro-magnetic source of energy for actuating said back spacing means, a normally closed switch in the circuit of said source of energy, said switch being operated by back spacing means and being opened and closed thereby upon each operation thereof, and means to control said source of energy.

3.A In a phonograph, a carriage, a sound box supported by the carriage, means to back space said carriage, electro-magnetic means for actuating said back spacing means, said actuating means comprising an electric circuit and a control device, and means operated by said back spacing means and adapted upon a single operation of said control device repeatedly to open and close said circuit.

4. In a phonograph, a carriage, a sound box supported by the carriage, means to back space said carriage, said means comprising an electromagnet and circuit for furnishing power to move said carriage in a backwardly direction each time said circuit is closed, and means comprising a movable switch member automatically operable concurrently with said back spacing means repeatedly to open and close the circuit of said magnet upon completion of each back spacing movement.

5. In a phonograph, a carriage, a sound box supported by the carriage, means to back space said carriage, an electro-magnetic source of energy for operating the back spacing means and biased to inoperative position with respect to said means, and means operated by said source of energy to open the circuit of the latter upon completion of the back spacing operation.

6. In a phonograph, a sound box carriage, back spacing means for said carriage, an electromagnet for actuating said back spacing means and rendered operable by the closing of the circuit of said magnet, a control switch operable at will to open or close said circuit, and a second switch in circuit with said control switch and actuated by said electromagnet to repeatedly open and close said circuit and to thereby energize said magnet to repeatedly back space said carriage, when said control switch is maintained closed.

'7. In a phonograph, a sound box carriage, back spacing means for said carriage, means comprising an electromagnet for actuating said back spacing means and rendered operable by the closing of the circuit of said magnet, a control switch operable at will to open or close said circuit, a movably mounted switch in series with said control switch and comprising a closed vessel having two electrodes at opposite ends thereof, and containing mercury adapted to establish electrical connection between the electrodes in one position of the switch and to break such connection when the switch is moved to another position, said second switch being actuated by said electromagnet to repeatedly open and close said circuit when said control switch is maintained closed.

8. In a phonograph, a frame, a sound box carriage mounted for transverse movement thereon, means for moving the carriage in an advancing direction, means for returning said carriage by xed amounts, a recurrently operable electromagnetic device or actuating said returningv means, and a control for said electro-magnetic device, said control comprising a plurality of switches, one of said switches being repeatedly operable by movement of said returning means when another of said switches is maintained closed.

9. In a phonograph, in combination, a carriage, a sound box supported by said carriage, means to back space said carriage by predetermined amounts, an electric circuit, a device for controlling flow of electric energy in said circuit, said circuit comprising an electro-magnet for actuating said back spacing means each time said magnet is energized, and a switch in said circuit operated by said back spacing means to repeatedly energize and de-energize said magnet when said control device is maintained in position to allow flow of electric energy in said circuit.

10. In a phonograph, in combination, a sound box carriage, back spacing means for said carriage, an electro-magnet for actuating said back spacing means upon each energization of the electric circuit of said magnet, a control device adapted to be maintained closed to energize said circuit, and a switch automatically operable with said back spacing means to open and close said circuit repeatedly when said control is maintained closed, said switch being operated upon each actuation of said back spacing means.

11. In a device of the class described, in combination, a carriage, a sound box carried by said carriage, mechanism :for back spacing said carriage, an electro-magnet for actuating said mechanism, a control device for energizing or deenergizing at will the circuit of said magnet, and a switch device in said circuit adapted to be operated by said mechanism to open and close said circuit upon each operation of said mechanism. A

THOMAS C. BROWN. 

